An experienced clinician with a long standing research interest will receive training in two Phases to prepare for a career in basic vision research. The training will be conducted under the supervision of a Sponsor who is an accomplished and active researcher in the applicant's areas of interest. During Phase I of the training the applicant will acquire a solid background in basic vision science, learn the research skills required to undertake high quality vision research, receive intensive laboratory research experience under the sponsor's direct supervision, complete research tutorials in the laboratories of at least two other active vision researchers, acquire special clinical skills relevant to his area of research interest, and prepare a detailed proposals for a basic research project of his own. The research project to be conducted during Phase II of the training seeks to unravel the relative contributions of neural resolution and spatial directionalization in optotype measures of acuity. The research will compare optotype acuity to thresholds for neural resolution (measured as th finest grating resolvable) to precision of directionalization (measured in a vernier alignment task) at a range of specific luminances, eccentricities, and in the presence and absence of flanking contours. The results will elucidate the roles of neural resolution and spatial directionalization in measures of human acuity.